RUI: Contribution of Retinal Melatonin to Circulating Melatonin and its Importance in Metamorphosis

本研究旨在探讨两栖类动物眼部褪黑激素的分泌及其在变态过程中的作用。脊椎动物眼睛的功能不限于视觉。关于环境光照周期的信息通过眼睛传递到昼夜节律系统，在许多非哺乳类脊椎动物中，眼睛中的视网膜为循环提供褪黑激素。两栖动物眼部褪黑激素分泌的程度知之甚少。本研究将利用眼切除术的技术，探讨无尾目蝌蚪在不同发育阶段眼睛对血液褪黑激素的相对贡献，以及视网膜褪黑激素、甲状腺激素和变态之间的关系。本项目还将研究光/暗周期对循环视网膜褪黑激素的影响，视网膜褪黑激素分泌与循环褪黑激素和甲状腺素的昼夜节律之间的关联，以及在单侧或双侧眼切除术后是否发生褪黑激素分泌的代偿性增加，以维持血液褪黑激素水平。这些研究将提高我们对褪黑激素在发育中的作用及其与光周期对变态影响的关系的理解。本研究结果对研究脊椎动物体内的激素相互作用和褪黑激素的作用具有重要意义。此外，这些结果可能有助于更好地了解影响两栖动物种群下降的环境因素。 该项目将与本科生一起进行，以发展他们的研究能力和经验，并提升他们的职业抱负。打算在大学教学中寻求职业生涯的博士后研究员也将合作一年，以获得在大学一级结合教学和研究的经验。因此，该项目将大大有助于国家科学基金会的目标，鼓励研究纳入本科课程，并提前发现，同时促进教学，培训和学习。

This study will examine the ocular secretion of melatonin and the role of this melatonin in amphibian metamorphosis. The function of the vertebrate eye is not restricted to vision. Information about the environmental lighting cycle is conveyed to the circadian system via the eye and, in many nonmammalian vertebrates, the retina in the eye contributes melatonin to the circulation. Little is known about the extent of ocular melatonin secretion in amphibians. The technique of opthalmectomy will be used to determine the relative contribution of the eye to blood melatonin at different developmental stages in anuran tadpoles, as well as the relationships between retinal melatonin, thyroid hormones, and metamorphosis. This project will also examine light/dark cycle influences on circulating retinal melatonin, the association between retinal melatonin secretion and the diel rhythms in circulating melatonin and thyroxine, and whether a compensatory increase in melatonin production occurs after unilateral or bilateral opthalmectomy in an effort to maintain blood melatonin levels. These studies should improve our understanding of the role of melatonin in development and its relationship to photoperiodic influences on metamorphosis. The findings of this research might have significance as well to the study of hormone interactions and the role of melatonin in vertebrates in general. Moreover, these results may contribute to a better understanding of the environmental factors that affect declining amphibian populations. This project will be carried out with undergraduate students, to develop their competence and experience in research and to upgrade their career aspirations. A postdoctoral fellow who intends to seek a career in college teaching will also collaborate for one year to acquire experience in combining teaching and research at the college level. Thus, the project will contribute substantially to the National Science Foundation's objective of encouraging the integration of research into undergraduate programs and to advance discovery while promoting teaching, training, and learning.